Embodiments generally relate to a system and method of detecting the presence of an object, such as merchandise within a retail establishment. More specifically, embodiments relate to a system and method of accurately determining movement of an object within a location.
Various businesses track products through the use of radio-frequency identification (RFID) systems. For example, RFID systems may be used to track products for purposes of inventory, logistics, and the like.
An RFID system is typically a wireless, non-contact system that uses radio-frequency (RF) electromagnetic fields to transfer data from a tag or label attached to an object in order to identify and track the object. In the retail clothing industry, for example, RFID tags may be secured to articles of clothing, for example.
Typically, an RFID system includes tags or labels attached to the objects that are to be tracked and identified. Two-way radio transmitter-receivers, such as interrogators or readers, send signals to the tag and read encoded responses from the tag. The readers transmit observations regarding the tag or label to a computer system running RFID software, for example.
Information may be stored electronically in a non-volatile memory of the tag. The RFID tag includes a small RF transmitter and receiver. An RFID reader transmits an encoded radio signal to interrogate the tag. The tag receives the message and responds with identification information. The identification information may be a unique tag serial number, or product-related information such as a stock number, lot or batch number, production date, or other specific information.
Because RFID tags have individual serial numbers, the RFID system, by way of an RFID reader, for example, is able to discriminate among several tags that are within the range of the RFID reader. In general, RFID tags may include an integrated circuit for storing and processing information, modulating and demodulating a radio-frequency (RF) signal, collecting direct current power from the incident reader signal, and other specialized functions, and an antenna for receiving and transmitting the signal.
An RFID system may be configured to detect a moving RFID tag within a particular location. Detection of a moving RFID tag is typically used to determine whether or not a product having an RFID tag is moving toward an exit of a location. Such information may be used to determine if the product is being unlawfully removed from the location. For example, if an RFID system detects that a product having an RFID tag is moving toward an exit of a store, the RFID system may generate an alert that the product is in jeopardy of being stolen. In general, detection of moving RFID tags affixed or secured to items is useful for security, as well as accurate inventory determination.
While businesses often track products for purposes of inventory, logistics, and the like through the use of RFID systems, many businesses also utilize separate and distinct theft-detection systems. For example, many retail stores include theft-detection systems proximate the entrance/exit of the particular stores.
As an example, various locations utilize electronic article surveillance (EAS) systems, which are often used to prevent theft and similar unauthorized removal of articles from a controlled area. Typically, a system transmitter and a system receiver are used to establish a surveillance zone, which must be traversed by any article being removed from the controlled area.
An EAS tag, which may be or include an RFID tag, may be affixed to each article and includes a marker or sensor adapted to interact with a signal that is transmitted by the system transmitter into the surveillance zone. The interaction causes a further signal to be established in the surveillance zone, which is received by the system receiver. Accordingly, upon movement of a tagged article through the surveillance zone, a signal is received by the system receiver, identifying the unauthorized presence of the tagged article in the zone.
Typically, however, a surveillance zone of an EAS system includes areas that are outside of a desired monitored area. For example, an EAS system may include backfield and/or over-range areas that are outside of a passage through which individuals pass into and out of a location. If an individual is within a backfield or over-range area, an alarm may be generated, despite the individual not being within the passage. In an attempt to minimize such false alarms, some systems utilize directional counting devices. For example, infrared transmitters and receivers may be secured to or proximate the EAS system at or proximate the portal. When the aligned beams are broken in a particular sequence, the system may determine that an individual is exiting a location. When used in conjunction with the EAS system, the directional counting devices may more accurately determine alarm events. However, if multiple individuals are present, the system may still yield false alarms. For example, if an individual with a tagged article is in a backfield or over-range area, and another individual without a tagged article passes through the exit portal, an alarm may erroneously be generated due to the system detecting the tag in the backfield or over-range area, and movement of the individual without the tagged article.